The present invention relates generally to manufacture of IC (integrated circuit) packages, and more particularly, to a mechanism for automatically preventing the transfer of an IC package from a temperature soaking chamber to a testing chamber when the IC package has not been placed within the temperature soaking chamber for a predetermined time period.
Referring to FIG. 1, during manufacture of IC (integrated circuit) packages, the IC packages are tested for proper functionality at a range of temperatures such as from about xe2x88x9240xc2x0 Celsius to about +85xc2x0 Celsius, for example. An example testing system that handles the IC packages for such testing of the IC packages for a range of temperatures is the MCT3608E Handler or the MCT3608CCA Handler available from Micro Component Technology, Inc. headquartered in St. Paul, Minn.
Referring to FIG. 1, such a temperature testing system 100 includes a testing chamber 102 and a temperature soaking chamber 104 having a heating or cooling grid 106. The heating or cooling grid 106 is heated or cooled such that the temperature within the soaking chamber 104 is at a predetermined temperature. IC packages are heated or cooled to the predetermined temperature within the soaking chamber 104 by placing the IC packages within the soaking chamber 104 for a predetermined time period. Such a process of heating or cooling the IC packages within the soaking chamber 104 is referred to as xe2x80x9csoakingxe2x80x9d the IC packages by one of ordinary skill in the art of IC package manufacture.
After the IC packages have been heated or cooled to the predetermined temperature within the soaking chamber 104, the IC packages are transferred to the testing chamber 102 for testing of electrical characteristics of the IC packages when the IC packages are at that predetermined temperature, as known to one of ordinary skill in the art of IC package manufacture. Referring to FIG. 1, the temperature testing system 100 includes a plurality of tracks including a first track 108 and a second track 110 for holding the IC packages through the temperature soaking chamber 104 to the testing chamber 102. A temperature testing system, such as the MCT3608E Handler or the MCT3608CCA Handler available from Micro Component Technology, Inc., typically includes more numerous tracks, such as thirteen tracks for example, but two tracks 108 and 110 are shown in FIG. 1 for clarity of illustration.
Each of the tracks 108 and 110 includes a respective input with a first input 112 for the first track 108 and a second input 114 for the second track 110. A container such as an IC tube for holding the IC packages is placed on the input of a track for transferring the IC packages from the container to the temperature soaking chamber 104. Referring to FIG. 1, a first prior IC tube 116 is placed on the first input 112 of the first track 108, and a second prior IC tube 118 is placed on the second input 114 of the second track 110. Referring to FIGS. 1 and 2, the IC packages from the first prior IC tube 112 are transferred to the first track 108 within the soaking chamber 104, and the IC packages from the second prior IC tube 114 are transferred to the second track 110 within the soaking chamber 104. Elements having the same reference number in FIGS. 1 and 2 refer to elements having similar structure and function.
Referring to FIG. 3, a side view of the temperature testing system 100 shows the IC packages, from the first prior IC tube 116 placed at the first input 112, sliding out of the first prior IC tube 116 and onto the first track 108 within the temperature soaking chamber 104. The side view of any track of the temperature testing system 100 including the second track 110 is similar to the side view of the first track 108 as illustrated in FIG. 3. Elements having the same reference number in FIGS. 1, 2, and 3 refer to elements having similar structure and function. An IC package detector 120 is disposed within the temperature soaking chamber near a first output stopper device 122 at the output of the first track 108. Referring to FIGS. 1 and 2, the first output stopper device 122 is at the output of the first track 108, and the second output stopper device 124 is at the output of the second track 110. The output of a track is the end of the track within the soaking chamber 104 near the testing chamber 102.
Referring to FIGS. 3 and 4, the IC package detector 120 is a position sensor such as an opto-electronic position sensor that detects when an object is adjacent to the IC package detector 120. Such position sensors are known to one of ordinary skill in the art of electronics. Referring to FIG. 4, when the track 108 is full of IC packages with an IC package being adjacent the IC package detector 120, the IC package detector 120 sends an xe2x80x9cIC package PRESENTxe2x80x9d control signal to a data processor 126 of the temperature testing system 100 to indicate that the soaking chamber 104 is full of newly transferred IC packages. Elements having the same reference number in FIGS. 1, 2, 3, and 4 refer to elements having similar structure and function.
The data processor 126 then starts a timer that times up to a predetermined time period from when the IC package detector 120 sends the xe2x80x9cIC package PRESENTxe2x80x9d control signal to the data processor 126 such that the IC packages on the track 108 are xe2x80x9csoakedxe2x80x9d to the predetermined temperature of the soaking chamber 104 by being placed within the soaking chamber 104 for the predetermined time period. For example, the predetermined time period may be about 4 minutes.
Referring to FIG. 5, after the predetermined time period from when the IC package detector 120 sends the xe2x80x9cIC package PRESENTxe2x80x9d control signal, the data processor 126 controls the output stopper device to be lowered to a passing position such that the IC packages on the track 108 may be transferred to the testing chamber 102. The IC packages are then transferred from the soaking chamber 104 to the testing chamber 102 for electrical testing of the IC packages at the predetermined temperature. Elements having the same reference number in FIGS. 1, 2, 3, 4, and 5 refer to elements having similar structure and function.
Referring to FIGS. 3, 5, and 6, as the IC packages of the first prior IC tube 116 are transferred to the testing chamber 102 after such IC packages have been soaked within the soaking chamber 104 for the predetermined time period, a subsequent IC tube 130 may be placed on the input 112 of the track 108. Elements having the same reference number in FIGS. 1, 2, 3, 4, 5, and 6 refer to elements having similar structure and function. The elements of the prior art temperature testing system 100, such as the elements of the MCT3608E Handler or the MCT3608CCA Handler available from Micro Component Technology, Inc., of FIGS. 1, 2, 3, 4, 5, and 6 are known to one of ordinary skill in the art of IC package manufacture
In the prior art temperature testing system 100, an operator keeps track of when the IC packages of the subsequent IC tube 130 are to be placed within the soaking chamber 104 after each of the IC packages of the first prior IC tube 116 has been transferred to the testing chamber 102. However, the operator may erroneously place the subsequent IC tube 130 of IC packages on the input 112 of the track 108 before each of the IC packages of the first prior IC tube 116 has been transferred to the testing chamber 102 as illustrated in FIG. 6.
In that case, the IC packages of the subsequent IC tube 130 are transferred onto the track 108 and may be transferred to the testing chamber 102 without being soaked within the soaking chamber 104 for the predetermined time period. The IC packages of the subsequent IC tube 130 that have not been properly soaked to the predetermined temperature of the soaking chamber 104 are tested in the testing chamber 102 when such IC packages are at an inappropriate temperature resulting in inaccurate testing of such IC packages.
Thus, a mechanism is desired for ensuring that the IC packages of the subsequent IC tube 130 are not transferred to the testing chamber 102 when such IC packages have not been soaked for the predetermined time period within the temperature soaking chamber 104.
Accordingly, in one embodiment of the present invention, a method and system includes a respective input stopper device at each input of the tracks for ensuring that each of a plurality of IC (integrated circuit) packages are placed within a temperature soaking chamber for the predetermined time period before being transferred to the testing chamber.
In a general aspect of the present invention, an input stopper device is disposed at an input of a track with the track being disposed through the temperature soaking chamber. A prior container holding a prior plurality of IC packages is placed at the input of the track such that the prior plurality of IC packages slides out of the prior container along the track into the soaking chamber when the input stopper device is at a passing position. The prior plurality of IC packages is placed within the soaking chamber for the predetermined time period before each of the prior plurality of IC packages is transferred to the testing chamber when an output stopper device at an output of the track within the soaking chamber is placed to a passing position. A control unit, coupled to the input stopper device, controls the input stopper device to be at a stopping position when any of the prior plurality of IC packages is within the soaking chamber and has not been transferred to the testing chamber. Thus, each of a subsequent plurality of IC packages of a subsequent container is blocked, by the input stopper device, to be contained within the subsequent container placed at the input of the track until each of the prior plurality of IC packages within the soaking chamber has been transferred to the testing chamber.
In addition, the control unit controls the input stopper device to be at the passing position after each of the prior plurality of IC packages has been transferred to the testing chamber and after the output stopper device is placed to a stopping position. Thus, each of the subsequent plurality of IC packages slides from the subsequent container along the track into the soaking chamber. Furthermore, each of the subsequent plurality of IC packages is blocked by the output stopper device from being transferred to the testing chamber until the subsequent plurality of IC packages has been within the soaking chamber for the predetermined time period.
In another aspect of the present invention, an IC package detector is disposed at the output of the track within the soaking chamber for detecting whether an IC package is present at the output of the track within the soaking chamber. In that case, the control unit controls the input stopper device to be at the stopping position when the IC package detector detects that an IC package is present at the output of the track indicating that any of the prior plurality of IC packages is within the soaking chamber. The output stopper device is placed to a stopping position after the IC package detector detects that no IC package is present at the output of the track. Furthermore, the control unit controls the input stopper device to be at the passing position when the IC package detector detects that no IC package is present at the output of the track and after the output stopper device has been placed to the stopping position.
The present invention may be used to particular advantage when the control unit includes a 5 second timer such that the input stopper device is placed to the stopping position about 5 seconds after the IC package detector begins to detect that an IC package is at the output of the track within the soaking chamber. Thus, all of the prior plurality of IC packages is placed within the soaking chamber before the input stopper device is placed to the stopping position.
Additionally, the control unit may include a 10 second timer such that the input stopper device is placed to the passing position about 10 seconds after the IC package detector begins to detect that no IC package is at the output of the track within the soaking chamber. Thus, the output stopper device is put to the stopping position before the input stopper device is placed to the passing position.
In this manner, each of the IC packages of the subsequent IC package container placed at the input of the track is blocked by the input stopper device from entering the temperature soaking chamber until each of the IC packages of the prior IC package container has been transferred to the testing chamber and until the output stopper device has been placed to the stopping position. After each of the IC packages of the prior IC package container has been transferred to the testing chamber and after the output stopper device has been placed to the stopping position, the input stopper device is placed to the passing position such that the IC packages of the subsequent IC package container are transferred to the soaking chamber. Then, after such IC packages have been within the soaking chamber for the predetermined time period, the output stopper device is placed to the passing position such that the IC packages of the subsequent IC package container are transferred to the testing chamber. Thus, each of the IC packages of the prior IC package container and the subsequent IC package container is placed within the soaking chamber for the predetermined time period before being transferred to the testing chamber for testing of the IC packages at the proper temperature.